PROJECT TITLE: Improvement of orchids and tulips through genetic engineering

Orchids is a major income earner for the country. A wide selection of hybrids is available but only a few are suitable for commercial undertaking. The use of conventional breeding methods to create variation orchids is not practical because of poor seed set prevalent in important hybrids. The genetic manipulation techniques can be an excellent approach for the production of new orchid varieties. Biotechnology research in orchids is planned and aimed primarily at developing new techniques for transformation and regeneration systems and at introducing desirable genes or changing endogenous expression.

Identification, isolation, characterization and transfering genes responsible for colours and increasing the shelf life of flowers are the focus of research in orchid improvement. Colour is an essential consideration in consumers preference. It is also an important factor in determining market price. The colour of orchid flowers is generally characteristic of the genes Phalaenopsis (pastel), Dendrobium and Vandas (dark). The major pigments involved in flower colour are authocynins and carotenoids. The biosynthesis of these pigments is controlled by a complex series of biochemical reactions involving several enzymes such as chalcone synthase (CHS), dihydroxy flavanone reductase (DFR) and flavanone-3-hydroxylase (F3-H). It is possible to use the information on the genes for these enzymes from other plants to gain an understanding of their role in orchids. Such an understanding would enable genetic manipulation (via antisense technology and cosuppression) to control the formation of colour in orchids according to market demand.

Senescence is due to the ethylene produced by the flower primarily at the onset of pollination. Since ethylene plays a major role in triggering flower senescence inhibiting or reducing the production of ethylene in flowers will delay senescence process. Two genes involved in the ethylene biosynthesis pathway, namely, ACC oxidase and ACC synthase have been cloned. The application of antisense RNA technology for inhibition of ACC oxidase/synthase to reduce the production of ethylene has been successfully demonstrated in tomatoes (now commercialized) for delayed ripening. This technology will be applied to orchids to produce pastel flower or other novel flower colour (solid yellow and blue). Various techniques have been developed to introduce foreign genes into plants.

The particle bombardment method has been successfully used for gene transfer in several plant species including orchids. The use of Agrobacterium-mediated gene transfer has also been reported in several monocotyledonous species and will be used for orchids. Similarly, the combination of these two methods will be investigated. Development of regeneration systems of the transformants will be systematically studied. The commercially available markers, i.e. the GUS- and kanamycin genes will be used in the initial stages of transformation studies. Other relevant genes will be obtained from research labs overseas. The hybrids orchids used will be the

Phalaenopsis, Dendrobium, Vandas and those that have potential commercial values. The genes that control flower colour and senescence in orchids will be used when they ready and made available by the researchers involved.

 

Among the major ornamental bulbs cultivated world wide, tulips ranks number one. In Malaysia, tulip pot plant or cut flower production is possible through the use of suitable cultivators and precise temperature control to produce quality plants. The first reported tulip forcing in Malaysia was carried out by Mekar Sdn. Bhd. In Bukit Larut, Perak in 1995. Some attempts to force the bulbs have been made by the Dept. of Agriculture. For a successful tulip production in Malaysia, a scientific and biotechnology approach is planned. This includes manipulation of temperature regimes for bulb storage and flowering time. The biotechnological technique proposed for tropical orchids and tulips should result in lucrative value-added products for the flower industry.

Objective Achived

• Orchid

1. Established regeneration systems (from protocorm-like-bodies, shoot-tips, callus) in all selected orchids hybrids studied (Dendrobium, Mokara, Oncidium)
2. Established a system using biolistic particle gun to introduce the genes of interest (flower colour) and monitor transgenes in orchid hybrids.
3. Reduced flowering time of orchid plants vis tissue culture manipulation to produce flowering in a flask (in vitro flowering) i.e. form a normal time of 3-5 years to 5-7 months.
4. Isolated the genes involved in orchids flower colour from Oncidium and increased shelf life from Phalaenopsis. The anti-sense constructs for the genes have been completed.

• Tulip

1. Capability to force flowering of tulip under warmer temperatures (21-18oC day/night)
2. The tulip bulbs, though still imported, can now be cured locally which reduce cost tremendously (by more than 200%).
3. The plant height (which tend to elongate at warm temperatures) of potted and cut-tulips can be controlled (execellent for post0harvest handling and for value-added properties).

Benefits of the Project

• New and improved orchid and tulip varieties with desirable colour traits and prolonging shelf life. The techniques developed offer the opportunity to scale up the production of any variants that has added value for commercialisation.
• Beneficiaries - The floriculture industry will definitely benefit from this project. Development of new varieties will provide options to suit then customers's needs. Increasing the shelf life of flower will reduce the cost of post-harvest loses.

Project Status

- Completed